1. Field of the Invention
The present invention relates to blade drive devices and optical devices.
2. Description of the Related Art
Conventionally, there has been known a blade drive device having a drive ring for applying a drive force to a blade, which adjusts an opening amount of an opening formed on a board (see Japanese Examined Patent Application Publication No. 07-92580).
In such a blade drive device, it is preferable to reduce and transmit the drive force from a drive source to the blade, in order to improve the positional accuracy of the blade. However, in order to reduce a speed of the drive force from the drive source, it is necessary to transmit the drive force to the drive ring via plural gears. There is a problem in which the blade drive device is increased in size due to the presence of such gear for reducing the speed.